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Description:
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The need for pathogen -free water supplies has spurred investigations into the use
of ionizing radiation for the treatment of wastewater effluent and municipal biosolids .
The objective of this research was to develop an electron -beam irradiation scenario to
effectively eliminate microbial pathogens from municipal biosolids and wastewater
effluent . The Monte Carlo N -Particle (MCNP5 ) radiation transport code was used to
simulate the irradiation scenario .
Using MCNP5 , dual electron -beam sources were modeled as planar
surface sources above and below a stainless steel delivery trough containing either
effluent water or one of two biosolids material compositions . A dose deposition analysis
was performed to assess both the planar dose distribution and 25 depth -dose curves . In
addition , a density perturbation study was performed to assess the variance in the dose
deposition for different mass solids concentrations . To validate the MCNP5 code for this type of application , a benchmark study was
performed . Two municipal biosolids materials and water were irradiated in plastic bags
on a conveyor belt using a 10 -MeV electron accelerator with the exit window below the
material . The experimental configuration was modeled with the MCNP5 radiation
transport code . Simplified and detailed models were created and analyzed .
Lastly , an economic analysis was performed to assess whether this treatment
method is a financially viable alternative to current wastewater treatment methods .
Processing capacity was calculated for two accelerator specifications . These capacity
rates in conjunction with the operating and capital costs per dry ton to irradiate the
material were compared with existing data for electron beam processing of municipal
biosolids . The cost breakdown was also compared with quoted costs for existing
conventional methods .
The models developed showed that the use of 10MeV electron -beam technology
for the treatment of wastewater effluent and municipal biosolids is effective and
economically feasible . The benchmarking study illustrated the accuracy of Monte Carlo
simulation for this type of application . The method development process was shown to
be adaptable for various material compositions and irradiation configurations . |